Otolaryngology - Research Publications
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ItemHybrid optogenetic and electrical stimulation for greater spatial resolution and temporal fidelity of cochlear activation(IOP PUBLISHING LTD, 2020-10)OBJECTIVE: Compared to electrical stimulation, optogenetic stimulation has the potential to improve the spatial precision of neural activation in neuroprostheses, but it requires intense light and has relatively poor temporal kinetics. We tested the effect of hybrid stimulation, which is the combination of subthreshold optical and electrical stimuli, on spectral and temporal fidelity in the cochlea by recording multiunit activity in the inferior colliculus of channelrhodopsin (H134R variant) transgenic mice. APPROACH: Pulsed light or biphasic electrical pulses were delivered to cochlear spiral ganglion neurons of acutely deafened mice, either as individual stimuli or as hybrid stimuli for which the timing of the electrical pulse had a varied delay relative to the start of the optical pulse. Response thresholds, spread of activation and entrainment data were obtained from multi-unit recordings from the auditory midbrain. MAIN RESULTS: Facilitation occurred when subthreshold electrical stimuli were applied at the end of, or up to 3.75 ms after subthreshold optical pulses. The spread of activation resulting from hybrid stimulation was significantly narrower than electrical-only and optical-only stimulation (p < 0.01), measured at equivalent suprathreshold levels of loudness that are relevant to cochlear implant users. Furthermore, temporal fidelity, measured as maximum following rates to 300 ms pulse trains bursts up to 240 Hz, was 2.4-fold greater than optical-only stimulation (p < 0.05). SIGNIFICANCE: By significantly improving spectral resolution of electrical- and optical-only stimulation and the temporal fidelity of optical-only stimulation, hybrid stimulation has the potential to increase the number of perceptually independent stimulating channels in a cochlear implant.
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ItemTissue Characterization Using Synchrotron Radiation at 0.7 THz to 10.0 THz with Extended ATR Apparatus Techniques(MDPI, 2022-11)The attenuated total reflection (ATR) apparatus, with an added partial reflection/partial transmission mode, was used to demonstrate a novel way of characterizing water-based substances at 0.7 to 10.0 THz at the Australian Synchrotron THz-far infrared beamline. The technique utilized a diamond-crystal-equipped ATR to track temperature-dependent changes in reflectance. A "crossover flare" feature in the spectral scan was noted, which appeared to be a characteristic of water and water-dominated compounds. A "quiet zone" feature was also seen, where no temperature-dependent variation in reflectance exists. The variation in these spectral features can be used as a signature for the presence of bound and bulk water. The method can also potentially identify the presence of fats and oils in a biological specimen. The technique requires minimal sample preparation and is non-destructive. The presented method has the promise to provide a novel, real-time, low-preparation, analytical method for investigating biological material, which offers avenues for rapid medical diagnosis and industrial analysis.
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ItemNo Preview AvailableElectrocochleography triggered intervention successfully preserves residual hearing during cochlear implantation: Results of a randomised clinical trial(ELSEVIER, 2022-12)BACKGROUND: Preservation of natural hearing during cochlear implantation is associated with improved speech outcomes, however more than half of implant recipients lose this hearing. Real-time electrophysiological monitoring of cochlear output during implantation, made possible by recording electrocochleography using the electrodes on the cochlear implant, has shown promise in predicting hearing preservation. Sudden drops in the amplitude of the cochlear microphonic (CM) have been shown to predict more severe hearing losses. Here, we report on a randomized clinical trial investigating whether immediate surgical intervention triggered by these drops can save residual hearing. METHODS: A single-blinded placebo-controlled trial of surgical intervention triggered when CM amplitude dropped by at least 30% of a prior maximum amplitude during cochlear implantation. Intraoperative electrocochleography was recorded in 60 adults implanted with Cochlear Ltd's Thin Straight Electrode, half randomly assigned to a control group and half to an interventional group. The surgical intervention was to withdraw the electrode in ½-mm steps to recover CM amplitude. The primary outcome was hearing preservation 3 months following implantation, with secondary outcomes of speech-in-noise reception thresholds by group or CM outcome, and depth of implantation. RESULTS: Sixty patients were recruited; neither pre-operative audiometry nor speech reception thresholds were significantly different between groups. Post-operatively, hearing preservation was significantly better in the interventional group. This was the case in absolute difference (median of 30 dB for control, 20 dB for interventional, χ² = 6.2, p = .013), as well as for relative difference (medians of 66% for the control, 31% for the interventional, χ² = 5.9, p = .015). Speech-in-noise reception thresholds were significantly better in patients with no CM drop at any point during insertion compared with patients with a CM drop; however, those with successfully recovered CMs after an initial drop were not significantly different (median gain required for speech reception score of 50% above noise of 6.9 dB for no drop, 8.6 for recovered CM, and 9.8 for CM drop, χ² = 6.8, p = .032). Angular insertion depth was not significantly different between control and interventional groups. CONCLUSIONS: This is the first demonstration that surgical intervention in response to intraoperative hearing monitoring can save residual hearing during cochlear implantation.
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ItemAcoustic Analysis of Slag Foaming in the BOF(MDPI, 2022-07)The control of slag foam that is produced during the Basic Oxygen Furnace (BOF) process has been the subject of significant research. The behaviour of slag foams is complex. Hence, the control of slag foam in the dynamic process of the BOF is challenging. Acoustic analysis of the BOF is one of the most promising methods for the indirect measurement of slag foam height. This paper reviews different studies on the fundamental behaviour of acoustics in liquid foams and various acoustic studies related to determining the slag foam height during the BOF process. Studies on the BOF have been carried out using both cold water models and plant trials, where acoustic measurements taken directly from the process were analysed. These studies showed that the attenuation of sound through liquid foam was influenced mainly by factors such as viscosity, bubble size, and foam height. Current systems are said to be 70 to 87 per cent accurate in detecting and/or predicting slopping events in the BOF, though there is a lack of systematic data in the literature to fully quantify this accuracy. There have been various attempts to combine sound with vibration and image signals to improve the prediction of slopping events in BOFs. The review substantiates the lack of accuracy of the current systems in determining the slag foam height using acoustic analysis and the need to address fundamental questions about the behaviour of sound in dynamic foam, its reliance on different factors, and the relatability of comparing cold model data to industrial data.
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ItemComparison of Quality of Life between Patients Undergoing Submental Endoscopic Thyroidectomy and Conventional Thyroidectomy: A Prospective Controlled Clinical Trial(MDPI, 2022-08)The objectives of this study were to compare the surgical outcomes and quality of life between patients undergoing submental endoscopic thyroidectomy and those undergoing conventional thyroidectomy. The surgical outcomes and quality of life were recorded. Forty-eight patients were included in the study. Their ages ranged from 20 to 60 years. All patients underwent lobectomy, isthmectomy, or the combination of lobectomy and isthmectomy. Most histological diagnoses were benign (85.42%). The submental endoscopic thyroidectomy group showed better scores in the energy/fatigue, emotional wellbeing, and general health domains (p = 0.006, 0.041, and 0.004, respectively). There were no statistically significant differences in surgical outcomes between the submental endoscopic thyroidectomy and conventional thyroidectomy groups (p > 0.05). Submental endoscopic thyroidectomy is feasible, and permits a better quality of life in terms of the energy/fatigue, emotional wellbeing, and general health domains.
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ItemAutomatic analysis of cochlear response using electrocochleography signals during cochlear implant surgery(PUBLIC LIBRARY SCIENCE, 2022-07-14)Cochlear implants (CIs) provide an opportunity for the hearing impaired to perceive sound through electrical stimulation of the hearing (cochlear) nerve. However, there is a high risk of losing a patient's natural hearing during CI surgery, which has been shown to reduce speech perception in noisy environments as well as music appreciation. This is a major barrier to the adoption of CIs by the hearing impaired. Electrocochleography (ECochG) has been used to detect intra-operative trauma that may lead to loss of natural hearing. There is early evidence that ECochG can enable early intervention to save natural hearing of the patient. However, detection of trauma by observing changes in the ECochG response is typically carried out by a human expert. Here, we discuss a method of automating the analysis of cochlear responses during CI surgery. We establish, using historical patient data, that the proposed method is highly accurate (∼94% and ∼95% for sensitivity and specificity respectively) when compared to a human expert. The automation of real-time cochlear response analysis is expected to improve the scalability of ECochG and improve patient safety.
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ItemNo Preview AvailableFungal otitis externa and tympanic membrane perforation: four-year experience at a Victorian hospital(AME Publishing Company, 2021-01-01)
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ItemNo Preview AvailableSpironolactone Ameliorates Cochlear Implant Induced Endolymphatic Hydrops.(Ovid Technologies (Wolters Kluwer Health), 2022-07-01)BACKGROUND: Endolymphatic hydrops (EH) has been observed in both animal and human cochleae following cochlear implant (CI) surgery. We tested whether EH could be eliminated by administration of mineralocorticoid steroid antagonist spironolactone and explored the electrophysiological consequences of this. METHODS: Sixty-four adult guinea pigs underwent cochlear implantation with a dummy electrode. Animals then survived either 2, 7, or 28 days. Auditory function was monitored by recording electrocochleography from the round window membrane preimplantation, and on the last day of the experiment. Spironolactone or control solution was added to animals' feed for 7 days (if they survived that long) beginning immediately prior to surgery. The presence of EH was determined using thin-sheet laser imaging microscopy. RESULTS: Treatment with spironolactone resulted in significant reduction in EH in the second cochlear turn 7 days postimplantation. In all animals, the compound action potential (CAP) threshold was elevated 2 days postimplantation, but for most frequencies had recovered substantially by 28 days. There was no treatment effect on CAP thresholds. SP/AP ratios were elevated at day 2. The amplitude growth of the CAP did not differ between test and control groups at any time after implantation. CONCLUSIONS: EH can be suppressed by antagonism of mineralocorticoid receptors in the week after cochlear implantation. Reduction in EH did not lead to any change in hearing, and there was no indication of synaptopathy signalled by reduced CAP amplitude at high sound intensities. We found no electrophysiological evidence that EH early after implantation impacts negatively upon preservation of residual hearing.
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ItemNo Preview AvailableBiologics for chronic rhinosinusitis(WILEY, 2021)BACKGROUND: This living systematic review is one of several Cochrane Reviews evaluating the medical management of patients with chronic rhinosinusitis. Chronic rhinosinusitis is common. It is characterised by inflammation of the nasal and sinus linings, nasal blockage, rhinorrhoea, facial pressure/pain and loss of sense of smell. It occurs with or without nasal polyps. 'Biologics' are medicinal products produced by a biological process. Monoclonal antibodies are one type, already evaluated in other inflammatory conditions (e.g. asthma and atopic dermatitis). OBJECTIVES: To assess the effects of biologics for the treatment of chronic rhinosinusitis. SEARCH METHODS: The Cochrane ENT Information Specialist searched the Cochrane ENT Register; CENTRAL (2020, Issue 9); Ovid MEDLINE; Ovid Embase; Web of Science; ClinicalTrials.gov; ICTRP and additional sources for published and unpublished studies. The date of the search was 28 September 2020. SELECTION CRITERIA: Randomised controlled trials (RCTs) with at least three months follow-up comparing biologics (monoclonal antibodies) against placebo/no treatment in patients with chronic rhinosinusitis. DATA COLLECTION AND ANALYSIS: We used standard Cochrane methodological procedures. Our primary outcomes were disease-specific health-related quality of life (HRQL), disease severity and serious adverse events (SAEs). The secondary outcomes were avoidance of surgery, extent of disease (measured by endoscopic or computerised tomography (CT) score), generic HRQL and adverse effects (nasopharyngitis, including sore throat). We used GRADE to assess the certainty of the evidence for each outcome. MAIN RESULTS: We included 10 studies. Of 1262 adult participants, 1260 had severe chronic rhinosinusitis with nasal polyps; 43% to 100% of participants also had asthma. Three biologics, with different targets, were evaluated: dupilumab, mepolizumab and omalizumab. All of the studies were sponsored or supported by industry. For this update (2021) we have included two new studies, including 265 participants, which reported data relating to omalizumab. Anti-IL-4Rα mAb (dupilumab) versus placebo/no treatment (all receiving intranasal steroids) Three studies (784 participants) evaluated dupilumab. Disease-specific HRQL was measured with the SNOT-22 (a 22-item questionnaire, with a score range of 0 to 110; minimal clinically important difference (MCID) 8.9 points). At 24 weeks, dupilumab results in a large reduction (improvement) in the SNOT-22 score (mean difference (MD) -19.61, 95% confidence interval (CI) -22.54 to -16.69; 3 studies; 784 participants; high certainty). At between 16 and 52 weeks of follow-up, dupilumab probably results in a large reduction in disease severity, as measured by a 0- to 10-point visual analogue scale (VAS) (MD -3.00, 95% CI -3.47 to -2.53; 3 studies; 784 participants; moderate certainty). This is a global symptom score, including all aspects of chronic rhinosinusitis symptoms. At between 16 and 52 weeks of follow-up, dupilumab may result in a reduction in serious adverse events compared to placebo (5.9% versus 12.5%, risk ratio (RR) 0.47, 95% CI 0.29 to 0.76; 3 studies, 782 participants; low certainty). Anti-IL-5 mAb (mepolizumab) versus placebo/no treatment (all receiving intranasal steroids) Two studies (137 participants) evaluated mepolizumab. Disease-specific HRQL was measured with the SNOT-22. At 25 weeks, the SNOT-22 score may be reduced (improved) in participants receiving mepolizumab (MD -13.26 points, 95% CI -22.08 to -4.44; 1 study; 105 participants; low certainty; MCID 8.9). It is very uncertain whether there is a difference in disease severity at 25 weeks: on a 0- to 10-point VAS, disease severity was -2.03 lower in those receiving mepolizumab (95% CI -3.65 to -0.41; 1 study; 72 participants; very low certainty). It is very uncertain if there is a difference in the number of serious adverse events at between 25 and 40 weeks (1.4% versus 0%; RR 1.57, 95% CI 0.07 to 35.46; 2 studies; 135 participants, very low certainty). Anti-IgE mAb (omalizumab) versus placebo/no treatment (all receiving intranasal steroids) Five studies (329 participants) evaluated omalizumab. Disease-specific HRQL was measured with the SNOT-22. At 24 weeks omalizumab probably results in a large reduction in SNOT-22 score (MD -15.62, 95% CI -19.79 to -11.45; 2 studies; 265 participants; moderate certainty; MCID 8.9). We did not identify any evidence for overall disease severity. It is very uncertain whether omalizumab affects the number of serious adverse events, with follow-up between 20 and 26 weeks (0.8% versus 2.5%, RR 0.32, 95% CI 0.05 to 2.00; 5 studies; 329 participants; very low certainty). AUTHORS' CONCLUSIONS: Almost all of the participants in the included studies had nasal polyps (99.8%) and all were using topical nasal steroids for their chronic rhinosinusitis symptoms. In these patients, dupilumab improves disease-specific HRQL compared to placebo. It probably also results in a reduction in disease severity, and may result in a reduction in the number of serious adverse events. Mepolizumab may improve disease-specific HRQL. It is very uncertain if there is a difference in disease severity or the number of serious adverse events. Omalizumab probably improves disease-specific HRQL compared to placebo. It is very uncertain if there is a difference in the number of serious adverse events. There was no evidence regarding the effect of omalizumab on disease severity (using global scores that address all symptoms of chronic rhinosinusitis).
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ItemSyringe with Nasal Applicator versus Syringe Alone for Nasal Irrigation in Acute Rhinosinusitis: A Matched-Pair Randomized Controlled Trial.(S. Karger AG, 2021)BACKGROUND/AIMS: Nasal saline irrigation is a common procedure to relieve nasal symptoms in upper respiratory tract diseases. There is no consensus on the recommended nasal saline delivery devices. The objectives of this study were to evaluate efficacy, satisfaction, adherence, and adverse effects in patients with acute upper respiratory tract diseases using a syringe with a nasal applicator for nasal irrigation. METHODS: Patients with acute nasopharyngitis, acute rhinitis, or acute rhinosinusitis were randomly allocated to use either (1) a syringe with a nasal applicator or (2) a syringe alone to irrigate one nostril. After the patients had completed irrigation with the allocated device in one nostril, they were instructed to perform nasal irrigation using the other device in the other nostril. All patients were instructed to use a syringe with a nasal applicator at home. The efficacy, satisfaction scores, adherence, and adverse effects were recorded. RESULTS: Sixty-four patients were enrolled. The mean age of the patients was 33.95 years (18-59 years). The mean duration of symptoms was 4.80 days. None of the enrolled patients regularly performed nasal irrigation. Forty-two had acute nasopharyngitis, 10 had acute rhinitis, and 12 had acute rhinosinusitis. At baseline, the mean overall efficacy score for the syringe with a nasal applicator was 8.17 ± 1.43, and that for the syringe alone was 5.95 ± 2.02 (MD 2.23, p < 0.001, 95% CI 1.75-2.70). At 1 week, the syringe with the nasal applicator had significantly higher scores in 3 of 4 domains, including symptom relief, ease of use, and patients' willingness to recommend the device to others, compared to baseline (p < 0.05). None of the enrolled patients had epistaxis, retained/dislodged the applicator during irrigation, or experienced an allergic reaction to the applicator after 1 week of nasal irrigation. CONCLUSION: Use of a syringe with an applicator for nasal irrigation yielded high scores in overall efficacy.